This invention relates to slitting stations for paper and the like and more particularly to a method of providing for the stable and accurate positioning of the paper as it passes through the cut point.
One common support means for a traveling web to be slit longitudinally is what is known as the wrap around slitter. An example of this type of slitter can be seen in U.S. Pat. No. 3,828,633. This type of machine generally utilizes a plurality of slitter bands and spacer tubes disposed on a single shaft or axis. The direction of travel of the web is changed by wrapping the web around the slitter bands. While this system provides firm support for the web in the area of the bands, there can be a tendency, particularly with respect to lightweight sheets or webs, for the web to draw down into the gap between the bands thus causing distortion and irregularities in the web. Further, the axial adjustment of the slitter bands and thus the adjustment of the width of the slit web is limited in this type of slitter.
Another type of slitter, known as a kiss type slitter, is usually used for high speed operation. Examples of such slitters can be seen in U.S. Pat. Nos. 3,143,024 and 3,785,232. In this type of slitter, a generally straight run or flat portion of the web is provided by passing the web over a pair of spaced apart rollers or support boards to change direction of the web and provide a flat draw or run of web in the slitter area. Heretofore these web support means have been spaced apart sufficiently to permit access to both top and bottom slitters and have provided substantially straight run of web. While this type of slitter usually accommodates infinite adjustment of slitters along the width of the web and provides for easy adjustment of slit width, the web can have a tendency to flutter or vibrate through the flat draw area, thus causing some irregularities in the slit.
The present invention provides a method and means for overcoming the above noted deficiencies. In accordance with the present invention, arcuate support board means are specially designed to wrap around one slitter element and extend to a point closely adjacent the overlap of the slitter elements and provide for an arcuate path and thus a stiff run of the paper right at the cut point. This generally arcuate configuration of the paper in the area of the cut point provides stability and avoids flutter which can be experienced in a substantially flat run of paper. In order to permit and facilitate ready access to the slitter elements, the support boards are pivotally mounted on a support table in such manner that they can be rotated away from each other and the slitter elements which they surround. The slitters can then be infinitely adjustable in a known manner along the support shaft. This also provides easy access to the slitters for maintenance.
It is an object, therefore, of the present invention to provide accurate support for a traveling web through a slitter station without inhibiting the lateral adjustability of the blades.
Other objects will be in part apparent and in part pointed out more in detail hereinafter.
The invention accordingly consists in the features of construction, combination of elements and arrangement of parts which can be exemplified in the construction hereinafter set forth in the scope of the application of which will be indicated in the appended claims.